1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display device. More particularly, the present invention relates to an OLED display device which is capable of not only compensating for a video voltage charged in each sub-pixel, but also simplifying a pixel circuit structure and a wiring structure and raising an aperture ratio, so as to further enhance picture quality, and a method for driving the same.
2. Discussion of the Related Art
Recently, a liquid crystal display, a field emission display, a plasma display panel and an organic light emitting diode (OLED) display have been highlighted as flat panel displays. Thereamong, the OLED display is a self-emissive device in which an organic light emitting layer emits light by recombination of electrons and holes, and is expected to be a next-generation display device owing to high luminance, low driving voltage and ultra-thinness thereof.
Such an OLED display device includes a plurality of sub-pixels, each of which includes an OLED having an organic light emitting layer disposed between an anode and a cathode, and a pixel circuit for independently driving the OLED.
The pixel circuit includes a plurality of switching transistors, at least one capacitor, and a driving transistor. The switching transistors charge a data signal in the capacitor in response to a scan signal generated in every horizontal period. The driving transistor controls the amount of current to be supplied to the OLED in response to a separate sense signal such that it corresponds to the level of a video voltage charged in the capacitor, thereby adjusting the gray scale of a corresponding sub-pixel.
A conventional pixel circuit configured in this manner should receive a scan signal and a sense signal that overlap during a certain period, respectively, through a plurality of gate lines to sequentially drive a plurality of switching transistors and a driving transistor. For this reason, a plurality of gate lines should be provided on a horizontal line basis to transmit a scan signal and a sense signal, respectively. This may result in a reduction in aperture ratio of each sub-pixel.